Method

Method
- block of code that you write that you can call from anywhere, anytime if it is included in that class and folder.
- Block of code that does one specific task
- Separate blocks of code to do specific action
ex. setHeight(), move(int x, int y)
- Reasoning call the same code over and over
- Names for method are always like the lowerCase toStart Upper After.
- Methods are always named like an Action and Verbs.
- A java method is a series of statements that perform some repeated task. Instead of writing 10 lines of code we can put those ten lines in a method and just call it in one line. It is like a shortcut.

Concept:
Instead of just repeating the following over and over again...

System.out.println("Attn: AP Computer Science");
System.out.println("Woodbridge Senior High School");
System.out.println("3001 Old Bridge Road");
System.out.println("Woodbridge VA 22192");
 
 

...we could just put it in a method like this...

public static void printHeader()
{
    System.out.println("Attn: AP Computer Science");
    System.out.println("Woodbridge Senior High School");
    System.out.println("3001 Old Bridge Road");
    System.out.println("Woodbridge VA 22192");
 
}
 

...and then all we'd have to do is call it using the method name...

printHeader();
 

...so it'll still print the same thing:
Attn: AP Computer Science
Woodbridge Senior High School
3001 Old Bridge Road
Woodbridge VA 22192


How to write a Method

public static void main (String[]args)
{
  // this is a method
  // void - returns nothing, just does what it says to do
  // main - the name of the method
  // names for methods are always like this lowerCastToStartUpperAfter
  // methods are always named like an action, verb
  // methods do something: actions or verbs
  // parameters or arguments are values that are being sent in
}
public <type><name>(<arguments/parameters>)
 
example:
public void move (int xChange, int yChange)
{
  // the code that moves your whatever you want based on xChange and yChange
  head.move(xChange, yChange);
}

an example of this move method would be:
move( 3, 3 );
which would move the object 3 to the right & 3 down


Types of Methods
Accessors: get info about your fields
-example: getHeight(), getNumBaths()
-example in code:

public class House
 
  {
       private int baths;
       private int bedrooms;
           //accessor methods
           public int getNumBaths()
      {
            return baths;
      }
           public int getNumBedrooms()
      {
           return bedrooms;
      }
  }
 
 
 
 
 

Mutator: changes things
-example: setHeight(), move(x,y)
-example in code:**

public class House
{
  private int numRooms;
  private int x,y;
 
  //mutator
  public void setNumRooms(int Num)
  {
    numRooms = num;
  }
  public void move (int xChange, yChange)
  {
    x = x + xChange;
    y = y + yChange;
  }
}
 
 

Remember, the method you create only works for the one program it's in unless other programs use the original one. Trying to call the method in a different class will not work unless there is some relationship established between the two.